The present invention relates to electronic solid state circuits of LSI and MSI types and more particularly to novel method and apparatus for yielding hybrid structures employing such solid state electronic circuitry to produce a hybrid package which is smaller, lighter in weight and has fewer input-output interconnections than are encountered in packages of conventional design.
Recent emphasis on hybrids, particularly in military applications, is toward the standardization of functions in packaging, having a high reliability level and a high level of quality while achieving lower cost and reduction in total occupied volume.
With the availability of LSI and MSI devices with complex functions, present trends are toward the development of more sophisticated circuit innovations using such devices with a minimum number of components. Other recent developments have been made in the field of synchro and data conversion modules and subsystems in which new product design and developement programs have been undertaken to fill the needs of both industrial and military markets, such products including CMOS synchro and resolver converters with 10- to 16-bit resolution and accuracies, 14-bit multiplying digital to analog converters (DAC's); video sample and hold circuits; high speed A/D converters; and active filters.
The assignee of the present invention has developed such products incorporating unique features in the design, packaging, processing, and manufacturing techniques. Considering one of these new product areas as exemplary, such as synchro products, a wide variety of synchro functions are currently available in discrete modules and multi-package hybrids. However, many end uses, such as airborne applications, require features among which are significant reductions in both size and weight, compactness, rugged design and high reliability and lower power. The assignee of the present invention has developed products fulfilling these requirements, as well as those of the Standard Electronic Module program specification, by focusing special attention on every level of design, packaging concept, processing, control, testing and the like.
The complexity and high component density of the circuits utilized to perform the necessary functions make it extremely difficult to design a hermetic package which is small enough to meet military and especially airborne specifications using standard hybrid packaging techniques. Thus the major problem is one of realizing adequate mounting area for passive and active components which is much greater than twice the available area of the desired package size without degrading or reducing the quality, reliability and environmental requirements. Also, the limitations encountered in fabrication techniques and materials further limit the size reductions presently capable of being obtained.